Reducing small colloidal particle concentrations in feed and/or byproduct fluids in the context of waterjet processing

ABSTRACT

A waterjet system in accordance with a particular embodiment includes a pressurizing device configured to pressurize a fluid, a cutting head downstream from the pressurizing device, and a catcher positioned to collect a jet from the cutting head. The system can further include a treatment assembly configured to treat a feed fluid to the pressurizing device and/or a byproduct fluid from the catcher, such as by removing submicron colloidal particles from the feed fluid and/or from the byproduct fluid. For example, the treatment assembly can include a coagulation unit, such as a chemical coagulation unit or an electrocoagulation unit, configured to coagulate the submicron colloidal particles. The pressurizing device, the cutting head, and the treatment assembly can be at different respective portions of a fluid-recycling loop.

CROSS-REFERENCE TO RELATED APPLICATIONS INCORPORATED BY REFERENCE

This application claims the benefit of the following applications:

(a) U.S. Provisional Application No. 61/860,166, filed Jul. 30, 2013;and

(b) U.S. Provisional Application No. 61/940,212, filed Feb. 14, 2014.

The foregoing applications are incorporated herein by reference in theirentireties. To the extent the foregoing applications or any othermaterial incorporated herein by reference conflicts with the presentdisclosure, the preset disclosure controls.

TECHNICAL FIELD

The present technology is generally related to the treatment of feedand/or byproduct fluids in the context of waterjet processing, such asclarifying feed and/or byproduct fluids in this context by coagulationor in another suitable manner.

BACKGROUND

Waterjet systems (e.g., abrasive jet systems) are used in precisioncutting, shaping, carving, reaming, and other material-processingapplications. During operation, waterjet systems typically direct ahigh-velocity jet of fluid (e.g., liquid water containing particles ofabrasive material) toward a workpiece to rapidly erode portions of theworkpiece. When compared to other material-processing technologies(e.g., grinding, plasma-cutting, etc.) waterjet processing can havesignificant advantages. For example, waterjet systems often producerelatively fine and clean cuts, typically without heat-affected zonesaround the cuts. Waterjet systems also tend to be highly versatile withrespect to the material type of the workpiece. The range of materialsthat can be processed using waterjet systems includes very softmaterials (e.g., rubber, foam, leather, and paper) as well as very hardmaterials (e.g., stone, ceramic, and hardened metal). Furthermore, inmany cases, waterjet systems are capable of executing demandingmaterial-processing operations while generating little or no dust,smoke, or other potentially toxic airborne byproducts.

In a typical waterjet system, a pressurizing device (e.g., adirect-drive plunger pump or an intensifier) pressurizes fluid to anultrahigh pressure, such as a pressure within a range from 30,000 psi to100,000 psi or more. Some of this pressurized fluid is routed through acutting head that includes an orifice element having an orifice. Theorifice element can be a hard jewel (e.g., a synthetic sapphire, ruby,or diamond) held in a suitable mount, such as a metal plate. Passingthrough the orifice converts static pressure of the fluid into kineticenergy, which causes the fluid to exit the cutting head as a jet at ahigh velocity (e.g., a velocity of up to 2,500 feet-per-second or more)and impact a workpiece. In some cases, an abrasive material (e.g.,garnet or silica) is entrained within the formed jet at a mixing chamberwithin the cutting head. Alternatively, and less typically, the fluidcan already contain entrained abrasive material before it reaches thecutting head. The use of abrasive material tends to facilitate erosivecutting, particularly for relatively dense workpiece materials. Aftereroding through a portion of the workpiece, the jet typically isdispersed in a fluid pool held within a catcher positioned below theworkpiece, thereby allowing the kinetic energy of the jet to dissipate.A jig including spaced-apart slats can be used to support the workpieceover the catcher. The jig, the cutting head, the workpiece, or acombination thereof can be movable under computer and/or robotic controlsuch that complex processing instructions can be executed automatically.

Conventionally, in the context of waterjet processing, using a feedfluid with relatively high hardness and/or a relatively highconcentration of total dissolved solids (“TDS”) is considered to beundesirable. This practice, for example, is thought to increase mineralprecipitation (e.g., scaling) on surfaces within waterjet systems.Ultrahigh pressures may exacerbate this problem by decreasing thesolubility of certain dissolved solids. It is thought that, over time,flakes of mineral precipitate may clog or otherwise damage fluidiccomponents of waterjet systems. Accordingly, some manufacturers ofwaterjet systems recommend using municipal water as a feed fluid andperiodically testing the hardness and the TDS concentration of thewater. If the hardness and/or the TDS concentration of the water is toohigh, softening by ion exchange and/or partial deionization by ionexchange or reverse osmosis may be recommended. Manufacturers ofwaterjet systems do not recommend complete or near-complete deionizationof feed fluids because this is known to cause the feed fluids to becomecorrosive. For example, instead of depositing mineral precipitates onsurfaces within waterjet systems, completely or nearly-completelydeionized feed fluids may tend to leach material (e.g., metal) fromthese surfaces. In addition to controlling the hardness and the TDSconcentration of feed fluids, filtering feed fluids with 0.4 micron bagfilters to trap large particles upstream from pressurizing devices ofwaterjet systems is also known. Thus, conventional approaches totreating feed fluids in the context of waterjet processing focus on thehardness of the feed fluids, the TDS concentration of the feed fluids,and the presence of large particles in the feed fluids. As discussedbelow, these approaches may be less effective, less efficient, and/orhave other disadvantages relative to approaches in accordance withembodiments of the present technology.

Independent of the treatment of feed fluids, byproduct fluids in thecontext of waterjet processing may have characteristics that presenttechnical challenges. When a jet including abrasive material dispersesin a fluid pool, fluid and particles of abrasive material within the jetbecome incorporated into the fluid pool. In at least some cases,particles of workpiece material liberated from processed workpieces arealso incorporated into the fluid pool. Eventually, the particles ofabrasive material and/or workpiece material accumulate in the fluid poolto unacceptable levels. Draining and disposing of the fluid pool iswasteful and can be costly when environmental issues preclude directdisposal into municipal sewer lines. Environmental issues are common,for example, when waterjet systems are used to process workpieces madeof toxic materials. Some approaches to treating byproduct fluids in thecontext of waterjet processing for disposal or reuse are known. Theseapproaches may rely heavily on filtration. As with conventionalapproaches to treating feed fluids, conventional approaches to treatingbyproduct fluids in the context of waterjet processing may be lesseffective, less efficient, and/or have other disadvantages relative toapproaches in accordance with embodiments of the present technology.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on clearlyillustrating the principles of the present technology. For ease ofreference, throughout this disclosure identical reference numbers may beused to identify identical or at least generally similar or analogouscomponents or features.

FIG. 1 is a block diagram illustrating a waterjet system in accordancewith an embodiment of the present technology including a treatmentassembly and having a first arrangement in which the treatment assemblyis configured to treat a byproduct fluid.

FIG. 2 is a block diagram illustrating a waterjet system in accordancewith an embodiment of the present technology including a treatmentassembly and having a second arrangement in which the treatment assemblyis configured to treat a feed fluid.

FIG. 3 is a block diagram illustrating a waterjet system in accordancewith an embodiment of the present technology including a treatmentassembly and having a third arrangement in which the treatment assemblyis configured to treat a fluid within a fluid-recycling loop.

FIG. 4 is a partially schematic perspective view of a waterjet system inaccordance with an embodiment of the present technology having the thirdarrangement shown in FIG. 3 and including a treatment assemblyconfigured for chemical coagulation.

FIG. 5 is a block diagram illustrating several interconnected componentsof the waterjet system shown in FIG. 4.

FIG. 6 is a partially schematic perspective view of a waterjet system inaccordance with an embodiment of the present technology having the thirdarrangement shown in FIG. 3 and including a treatment assemblyconfigured for electrocoagulation.

FIG. 7 is a block diagram illustrating several interconnected componentsof the waterjet system shown in FIG. 6.

FIG. 8 is a cross-sectional profile view of an electrocoagulation unitof the treatment assembly of the waterjet system shown in FIG. 6.

FIG. 9 is a partially cross-sectional profile view of a separation unitof the treatment assembly of the waterjet system shown in FIG. 6.

FIG. 10 is a flow chart illustrating a method for operating the waterjetsystem shown in FIG. 1 in accordance with an embodiment of the presenttechnology.

FIG. 11 is a flow chart illustrating a method for operating the waterjetsystem shown in FIG. 2 in accordance with an embodiment of the presenttechnology.

FIG. 12 is a flow chart illustrating a method for operating the waterjetsystem shown in FIG. 4 in accordance with an embodiment of the presenttechnology.

FIG. 13 is a flow chart illustrating a method for operating the waterjetsystem shown in FIG. 6 in accordance with an embodiment of the presenttechnology.

DETAILED DESCRIPTION

In the context of waterjet processing, the inventors have discovered adramatic and unexpected phenomenon associated with a characteristic offeed fluids that has been previously overlooked or at leastunderappreciated. As discussed above, attention to the quality of feedfluids in the context of waterjet processing has previously focused onthe hardness of the feed fluids, the TDS concentration of the feedfluids, and the presence of large particles in the feed fluids. Theinventors have discovered, however, a strong correlation between theconcentration of small colloidal particles in feed fluids and theservice life of seals within pressurizing devices of waterjet systems.For example, in an experiment, targeted removal of small colloidalparticles in liquid water fed to an ultrahigh pressure direct-driveplunger pump was shown to reduce average material loss per millionstokes from seals within the pump to nearly negligible levels. This isan important discovery for the waterjet industry. The need to frequentlyreplace pump seals in conventional waterjet systems is a common problemthat causes significant labor, system downtime, and other costs. Thesecosts can cause the economy of waterjet processing to compareunfavorably to that of other material-processing technologies forcertain applications. Accordingly, reducing or eliminating these costsis highly desirable. Furthermore, the observed correlation suggests thatother benefits may be associated with reducing the concentration ofsmall colloidal particles in feed fluids in the context of waterjetprocessing. These benefits may become known over time as waterjetsystems in accordance with embodiments of the present technology aredeployed in the field and put to heavy long-term use.

There are several possible explanations for the conventional failure torecognize or at least to fully appreciate the detrimental effect ofsmall colloidal particles in feed fluids in the context of waterjetprocessing. As one possibility, it may have been thought that the sizeof these particles would preclude their involvement in wear processesoccurring within fluidic components of waterjet systems. As anotherpossibility, the relatively low concentrations of these particles intypical sources of feed fluids, such as municipal water supplies, mayhave discounted their perceived significance. Colloidal particles indrinking water are generally considered to be a greater threat to humanhealth than dissolved solids. Thus, in most municipal water, theconcentration of colloidal particles is carefully monitored andaggressively lowered to consistent levels according to standardsmandated by government agencies. In contrast, controlling TDSconcentration in municipal water is often voluntary. TDS concentrationis known to vary widely among municipalities. In most municipal water,the weight-to-volume concentration of dissolved solids is much higher(e.g., 10 to 20 times higher) than the weight-to-volume concentration ofcolloidal particles.

In any case, the conventional failure to recognize or at least to fullyappreciate the detrimental effect of small colloidal particles in feedfluids in the context of waterjet processing contributed to thedevelopment of ineffective, inefficient, and/or otherwise inadequatetreatment protocols. The most common conventional protocols for treatingfeed fluids in this context include ion exchange and simple coarsefiltration. These protocols do not significantly decrease theconcentration of small colloidal particles in feed fluids. Reverseosmosis can be used to significantly decrease the concentration of smallcolloidal particles in feed fluids, but its conventional use in thecontext of waterjet processing tends to be wasteful and expensive.Furthermore, high concentrations of small colloidal particles in feedfluids treated by reverse osmosis would quickly overwhelm reverseosmosis filter membranes, thereby increasing the cost of reverse osmosisand decreasing its practicality. With respect to feed fluids most inneed of treatment (i.e., those with the highest concentrations of smallcolloidal particles), the economic disincentives to use reverse osmosisare greater than they are with respect to feed fluids least in need oftreatment (i.e., those with the lowest concentrations of small colloidalparticles). For this reason, reverse osmosis is not conventionally usedto treat byproduct fluids from waterjet processing, which, as discussedbelow, are often heavily laden with small colloidal particles.

By recognizing that reducing the concentration of small colloidalparticles, rather than merely reducing the hardness, the TDSconcentration, or the presence of large particles, should be the primaryfocus of treating feed fluids in the context of waterjet processing, theinventors have been able to develop advantageous new treatment protocolsuseful in a broad spectrum of waterjet applications. At least some ofthese protocols include coagulation, such as chemical coagulation orelectrocoagulation. By way of theory, and not wishing to be bound bytheory or to otherwise limit the scope of the present technology, smallcolloidal particles may carry a charge that tends to cause theseparticles to repel one another. Coagulation can include neutralizing orat least reducing this charge, thereby allowing the small colloidalparticles to coagulate in response to intermolecular attractive forces(e.g., van der Waals' force) into larger particles that can be moreeasily removed from a fluid. For example, in the case of chemicalcoagulation, a chemical coagulant added to a fluid including smallcolloidal particles may interact with the particles to cause theparticles to coagulate. As another example, in the case ofelectrocoagulation, electrodes may be used to release metal ions into afluid and small colloidal particles within the fluid may coagulate byinteracting with the metal ions, with surfaces of the electrodes, and/orwith electrolysis products associated with operation of the electrodes.

In addition to or instead of treating feed fluids in the context ofwaterjet processing, at least some embodiments of the present technologycan be used to treat byproduct fluids. Ironically, while waterjetsystems have been discovered to be exceptionally sensitive to thepresence of small colloidal particles in feed fluids, the same systemsalso tend to be exceptionally prone to generating these particles inbyproduct fluids. For example, particles of abrasive material entrainedin a jet often break apart into small fragments when the jet impacts aworkpiece. Similarly, small fragments of workpiece material may beliberated from a workpiece when a jet impacts the workpiece. Mostabrasive materials and many workpiece materials are relatively brittle.Such materials may be more prone to this behavior than other, moreductile materials. Furthermore, the extreme impact forces associatedwith waterjet processing may cause the fragmentation of abrasivematerials and/or workpiece materials to be relatively widespread andaggressive, resulting in unusually high numbers of fragments andunusually small fragment sizes. The small fragments that result fromwaterjet processing tend to form highly persistent small colloidalparticles that complicate reuse or disposal of byproduct fluids.Mechanisms for comparably prolific generation of small colloidalparticles may not exist, or at least may not exist to the same degree,in other material-processing applications. Albeit unlikely, if any othermaterial-processing applications are, in fact, comparable to waterjetapplications with respect to their tendency to generate small colloidalparticles, at least some embodiments of the present technology areexpected to be useful in such applications.

Some types of contamination within byproduct fluids in the context ofwaterjet processing are relatively straightforward to remove. Forexample, large particles of abrasive material, workpiece material, orother types of material may tend to sink or float in a fluid pool withina catcher of a waterjet system. These particles can be dredged orskimmed from the catcher before the fluid pool is drained.Alternatively, these particles can be shoveled, vacuumed, or otherwisecollected from the catcher after the fluid pool is drained. In somecases, recovered large particles of abrasive material are processed andrecycled. For example, recovered large particles of abrasive materialcan often be dried, screened, and reused for the same or a differentmaterial-processing application. In other cases, recovered largeparticles of abrasive material may be disposed of as solid waste. Aftermost or all large particles of abrasive material and/or workpiecematerial have been removed from a byproduct fluid, the remainingbyproduct fluid may still be heavily contaminated. Treating thisremaining byproduct fluid to produce a product having sufficient purityfor reuse as a feed fluid in the same or a different waterjet system innot trivial. This is particularly true given the inventors' discoveriesthat waterjet systems tend to be highly sensitive to the presence ofsmall colloidal particles in feed fluids even at relatively lowconcentrations and that waterjet applications are exceptionally prone togenerating problematic small colloidal particles. In some cases, evensimply treating a remaining byproduct fluid to produce a product havingsufficient purity for direct disposal into a municipal sewer line may betechnically challenging.

Systems, devices, and methods in accordance with embodiments of thepresent technology can at least partially address one or more of theproblems described above and/or other problems associated withconventional technologies whether or not stated herein. For example,waterjet systems in accordance with at least some embodiments of thepresent technology have features that facilitate fluid recycling atrelatively low cost and without unduly compromising performance ordurability. Specific details of systems, devices, and methods inaccordance with several embodiments of the present technology aredisclosed herein with reference to FIGS. 1-13. Although the systems,devices, and methods may be disclosed herein primarily or entirely withrespect to waterjet applications, other applications in addition tothose disclosed herein are within the scope of the present technology.Furthermore, it should understood, in general, that other systems,devices, and methods in addition to those disclosed herein are withinthe scope of the present technology. For example, systems, devices, andmethods in accordance with embodiments of the present technology canhave different and/or additional configurations, components, andprocedures than those disclosed herein. Moreover, a person of ordinaryskill in the art will understand that systems, devices, and methods inaccordance with embodiments of the present technology can be without oneor more of the configurations, components, and/or procedures disclosedherein without deviating from the present technology.

Waterjet systems in accordance with embodiments of the presenttechnology can be used with a variety of suitable fluids, such as water,aqueous solutions, hydrocarbons, glycols, and nitrogen. As such,although the term “waterjet” is used herein for ease of reference,unless the context clearly indicates otherwise, the term refers to a jetformed by any suitable fluid, and is not limited exclusively to water oraqueous solutions. The term “fluid,” as used herein, encompasses anysuitable fluid phase depending on the context. Furthermore, the term“fluid,” as used herein, may be substituted in suitable instances withany of the narrower terms “aqueous fluid,” “water,” “liquid,” “aqueousliquid,” and “liquid water” to indicate common examples of suitablefluids in the context of waterjet processing.

References herein to “ultrahigh pressures” refer to pressures suitablefor waterjet processing. For example, the “ultrahigh pressures”described herein can be pressures greater than 30,000 psi, such aspressures within a range from 30,000 psi to 120,000 psi. Referencesherein to “small colloidal particles” refer to particles that are (a)smaller than typical particles conventionally targeted for removal fromfeed fluids by simple coarse filtration in the context of waterjetprocessing and (b) larger than typical ions conventionally targeted forremoval from feed fluids by ion exchange in the context of waterjetprocessing. For example, the “small colloidal particles” describedherein can be colloidal particles having an average sieve diameterwithin a range from 0.002 to 0.4 microns or colloidal particlesotherwise consistent with the smallest fraction of colloidal fragmentsof abrasive material that commonly result from waterjet processing.Furthermore, the phrase “small colloidal particles,” as used herein, maybe substituted in suitable instances with any of the narrower phrases“small fragments of abrasive material,” “submicron fragments of abrasivematerial,” “small particles of pulverized abrasive material” and“submicron particles of pulverized abrasive material” to indicate commonexamples of relevant small colloidal particles in the context ofwaterjet processing.

Selected Examples of Waterjet Systems

FIG. 1 is a block diagram illustrating a waterjet system 1000 inaccordance with an embodiment of the present technology. The system 1000can include a reservoir 1002 configured to receive a fluid from a fluidsource 1004. The system 1000 can further include a pressurizing device1006, a cutting head 1008, a catcher 1010, and a treatment assembly 1012operably connected to one another and to the reservoir 1002 atsuccessively further positions downstream from the reservoir 1002. Inthe illustrated embodiment, the system 1000 has a first arrangement inwhich the treatment assembly 1012 is configured to treat a fluid fromthe catcher 1010 and then to discharge the fluid to a waste destination1014. Waterjet systems in accordance with other embodiments of thepresent technology can have other suitable arrangements. For example,FIG. 2 is a block diagram illustrating a waterjet system 1100 inaccordance with an embodiment of the present technology having a secondarrangement in which the treatment assembly 1012 is upstream from thereservoir 1002 and configured to treat a feed fluid from the fluidsource 1004.

FIG. 3 is a block diagram illustrating a waterjet system 1200 inaccordance with an embodiment of the present technology having a thirdarrangement in which the treatment assembly 1012 is configured to treata fluid within a fluid-recycling loop 1202. The fluid-recycling loop1202 can include a first portion 1202 a, a second portion 1202 b, athird portion 1202 c, and a fourth portion 1202 d, with the second,third, and fourth portions 1202 b-1202 d at successively furtherpositions downstream from the first portion 1202 a during a pass throughthe fluid-recycling loop 1202 originating at the first portion 1202 a.The reservoir 1002, the pressurizing device 1006, the cutting head 1008,the catcher 1010, and the treatment assembly 1012 can be operablyassociated with one another (e.g., fluidically connected to one another)within the fluid-recycling loop 1202. For example, the pressurizingdevice 1006 can be at the first portion 1202 a, the cutting head 1008and the catcher 1010 can be at the second portion 1202 b, the treatmentassembly 1012 can be at the third portion 1202 c, and the reservoir 1002can be at the fourth portion 1202 d of the fluid-recycling loop 1202.Other arrangements are also possible. To avoid redundancy, fluidtreatment techniques and certain other aspects of the present technologymay be described below primarily or entirely in the context of waterjetsystems having the third arrangement. In general, however, these aspectsof the present technology may also be useful in the context of waterjetsystems having the first, second, and other suitable arrangements.

FIG. 4 is a partially schematic perspective view of a waterjet system1300 in accordance with an embodiment of the present technology havingthe third arrangement (FIG. 3) and including a treatment assembly 1302configured for chemical coagulation. The system 1300 can include apressurizing device 1304 (shown schematically) (e.g., a direct-driveplunger pump or an intensifier) configured to receive a fluid movingthrough a fluid-recycling loop encompassing the treatment assembly 1302.The system 1300 can further include a cutting head 1306 operablyconnected to the pressurizing device 1304 and downstream therefrom.Extending between the pressurizing device 1304 and the cutting head1306, the system 1300 can include an ultrahigh pressure conduit 1308. Atan intermediate position along the ultrahigh pressure conduit 1308, thesystem 1300 can include an ultrahigh pressure joint 1309, such as anultrahigh pressure swivel joint or another suitable ultrahigh pressurejoint having two or more degrees of freedom. The pressurizing device1304 can be configured to pressurize the fluid to an ultrahigh pressuresuitable for waterjet processing. Correspondingly, the ultrahighpressure conduit 1308, the ultrahigh pressure joint 1309, and othercomponents of the system 1300 configured to carry the fluid between thepressurizing device 1304 and the cutting head 1306 can have pressureratings and/or other attributes that cause these components to becompatible with an ultrahigh pressure suitable for waterjet processing.

The cutting head 1306 can include a jet outlet 1310 and can beconfigured to direct a jet (not shown) including the fluid toward aworkpiece (also not shown) via the jet outlet 1310. The system 1300 canfurther include a base 1312, a user interface 1314 supported by the base1312, and an actuator 1316 configured to move the cutting head 1306relative to the base 1312. The base 1312 can include a catcher 1318(e.g., an open-air tank) positioned to collect the jet in a fluid pool(not shown) after the jet passes through the workpiece. In theillustrated embodiment, the catcher 1318 is static. In otherembodiments, the catcher 1318 can be replaced with a catcher configuredto move with the cutting head 1306 when the system 1300 is used toprocess relatively large workpieces. With reference again to FIG. 4, theactuator 1316 can be configured to move the cutting head 1306 along aprocessing path (e.g., a cutting path) in two or three dimensions and,in some cases, to tilt the cutting head 1306 relative to the base 1312.The ultrahigh pressure joint 1309 can facilitate this movement of thecutting head 1306 relative to the base 1312.

The system 1300 can further include an abrasive-delivery apparatus 1322configured to feed particles of abrasive material (not shown) from anabrasive material source 1324 (shown schematically) to the cutting head1306. The abrasive-delivery apparatus 1322 can include a hopper 1326, anabrasive-metering valve 1328 downstream from the hopper 1326, and anabrasive-delivery conduit 1330 downstream from the abrasive-meteringvalve 1328. In some embodiments, the particles of abrasive material flowfrom the hopper 1326 into the abrasive-delivery conduit 1330 via theabrasive-metering valve 1328 by gravity and then flow through theabrasive-delivery conduit 1330 toward the cutting head 1306 partially orentirely in response to a Venturi effect associated with the jet. Inother embodiments, the particles of abrasive material can be fed to thecutting head 1306 in another suitable manner. Within the cutting head1306, the particles of abrasive material can accelerate with the jetbefore impacting the workpiece. The abrasive-delivery apparatus 1322 canbe configured to move with the cutting head 1306 relative to the base1312 or to be stationary, such as to be stationary while the cuttinghead 1306 moves relative to the base 1312.

As shown in the cut-away portion of FIG. 4, the catcher 1318 can includea catcher outlet 1332 through which the fluid, contaminated withpulverized abrasive material, can be drained from the fluid pool. In theillustrated embodiment, the catcher outlet 1332 extends outwardly fromjust below an expected fluid level within the catcher 1318 at an upperportion of a sidewall of the catcher 1318. In other embodiments, thecatcher outlet 1332 can extend outwardly from a lower portion of thesidewall, from the bottom of the catcher 1318, or from another suitableportion of the catcher 1318. Positioning the catcher outlet 1332 toextend outwardly from an upper portion of the sidewall of the catcher1318 can be useful, for example, to reduce egress of sunken particles ofabrasive material and/or workpiece material from the catcher 1318 viathe catcher outlet 1332. In some embodiments, these sunken particles mayexit the catcher 1318 via another outlet (not shown), such as an outletextending outwardly from the bottom of the catcher 1318. In otherembodiments, these sunken particles may collect in the catcher 1318 andbe removed occasionally (e.g., using a shovel or a vacuum) with orwithout draining the fluid pool. In still other embodiments, the catcheroutlet 1332 can be positioned to encourage egress of sunken particlesfrom the catcher 1318 along with the fluid. Furthermore, the catcheroutlet 1332 can be fixed or moveable. For example, when movable, thecatcher outlet 1332 can be attached to a moveable submersible pump (notshown) configured to be placed within the catcher 1318. As anotherexample, the catcher outlet 1332, when movable, can be positioned at theend of a movable handheld collection tube (also not shown).

With reference again to FIG. 4, upstream from the pressurizing device1304, the system 1300 can include a reservoir 1334 configured to supplythe pressurizing device 1304 with the fluid. The treatment assembly 1302can be operably connected to the catcher 1318 and to the pressurizingdevice 1304 and positioned therebetween within the fluid-recycling loop.For example, the treatment assembly 1302 can be configured to receivethe fluid, in a contaminated state, from the catcher 1318 and to removesmall colloidal particles from the fluid so as to cause the fluid to besufficiently clarified to be supplied to the reservoir 1334 for reuse inthe pressurizing device 1304. The treatment assembly 1302 can includetwo or more assembly-level inlets 1336 (individually identified asassembly-level inlets 1336 a-1336 c) and two or more assembly-leveloutlets 1338 (individually identified as assembly-level outlets 1338a-1338 c) that can be used to connect the treatment assembly 1302 tomultiple catchers and to multiple reservoirs, such as catchers andreservoirs respectively corresponding to different waterjet-processingstations within a multi-station waterjet-processing operation.Alternatively, the treatment assembly 1302 can be dedicated to a singlecatcher and to a single reservoir.

Connecting conduits 1340 a, 1340 b, 1340 c (collectively identified asconnecting conduits 1340) suitable for carrying the fluid canrespectfully extend between the catcher outlet 1332 and theassembly-level inlet 1336 a of the treatment assembly 1302, between theassembly-level outlet 1338 a of the treatment assembly 1302 and thereservoir 1334, and between the reservoir 1334 and the pressurizingdevice 1304. The reservoir 1334, the pressurizing device 1304, thecutting head 1306, the catcher 1318, and the treatment assembly 1302,among other components of the system 1300 can be operably associatedwith one another (e.g., fluidically connected to one another) within thefluid-recycling loop. The system 1300 can be configured to move (e.g.,to automatically move) fluid from the catcher 1318 to the treatmentassembly 1302, from the treatment assembly 1302 to the reservoir 1334,from the reservoir 1334 to the pressurizing device 1304, from thepressurizing device 1304 to the cutting head 1306, and from the cuttinghead 1306 to the catcher 1318. The overall flow of the fluid through thefluid-recycling loop and segments of the overall flow of the fluidthrough the fluid-recycling loop can be intermittent or continuous atsteady state. Furthermore, there can be one or more manual operationsand/or breaks in the fluid-recycling loop. For example, the catcher 1318may be configured to be drained into a holding tank (not shown) and thetreatment assembly 1302 may be configured to draw the fluid from theholding tank. In some embodiments, a fluid source 1341 (shownschematically) is operably connected to the fluid-recycling loop at thereservoir 1334 for providing make-up fluid. In other embodiments,make-up fluid can be provided in another suitable manner. For example,the fluid source 1341 can be operably connected to the fluid-recyclingloop at the catcher 1318, at the treatment assembly 1302, or at anothersuitable position within the fluid-recycling loop.

As shown in FIG. 4, the system 1300 can further include a first levelsensor 1342 (shown schematically) disposed at least partially within thereservoir 1334 and configured to detect a fluid level within thereservoir 1334. Similarly, the system 1300 can include a second levelsensor 1344 (shown schematically) disposed at least partially within thecatcher 1318 and configured to detect a fluid level within the catcher1318. The system 1300 can further include a controller 1346 (shownschematically) having processing circuitry 1348 (also shownschematically) and memory 1350 (also shown schematically). Thecontroller 1346 can be operably connected to the user interface 1314, tothe treatment assembly 1302, and to the first and second level sensors1342, 1344. The memory 1350 can store instructions (e.g., non-transitoryinstructions) that, when executed by the controller 1346 using theprocessing circuitry 1348, control certain aspects of operation of thesystem 1300. Several example of these aspects are discussed below withreference to FIGS. 5 and 12.

In the illustrated embodiment, the treatment assembly 1302 is containedwithin a rectangular housing 1352 that is not fixedly connected to thebase 1312. In other embodiments, the housing 1352 can be eliminated orhave another suitable form. For example, at least a portion of thetreatment assembly 1302 can be fixedly connected to the base 1312, tothe pressurizing device 1304, or to both. Furthermore, the treatmentassembly 1302 can be stationary or mobile. For example, when thetreatment assembly 1302 is mobile, the housing 1352 can be replaced witha housing that includes wheels and can be readily moved to differentwaterjet-processing stations within a multi-station waterjet-processingoperation. This can be useful, for example, to facilitate collectingfluid from different catchers within a multi-station waterjet-processingoperation without necessitating the use of long collection hoses.Various other structural configurations of the treatment assembly 1302are also possible. Furthermore, the treatment assembly 1302 can beoperably connected to various combinations of support elements, such aspower supplies, material supplies, and waste destinations. In theillustrated embodiment, the treatment assembly 1302 is operablyconnected to a coagulant supply 1354, a supplemental solute supply 1356,and a waste destination 1358, all shown schematically.

FIG. 5 is a block diagram illustrating several interconnected componentsof the system 1300. For clarity of illustration, pumps and othercomponents for conveying the fluid into, out of, and through thetreatment assembly 1302 are not shown. Such components can be includedin or otherwise associated with the treatment assembly 1302 as needed toachieve suitable fluid motion and containment. As shown in FIG. 5, thetreatment assembly 1302 can include an intake filter 1400 configured toremove large particles from the fluid received from the catcher 1318. Insome embodiments, the intake filter 1400 is a bag filter or anothersuitable type of filter nominally rated for removal of at least 90% ofparticles larger than a relatively large threshold size (e.g., 5microns, 50 microns, or 100 microns). The intake filter 1400 can beconfigured to at least generally allow passage of small colloidalparticles. In other embodiments, the intake filter 1400 can have othersuitable specifications. Including the intake filter 1400 in thetreatment assembly 1302 can be useful, for example, to at leastpartially prevent relatively large particles from interfering with theoperation of downstream components of the treatment assembly 1302. Inaddition to or instead of the intake filter 1400, the treatment assembly1302 can include a settling weir system (not shown) serving a similarpurpose. A settling weir system, for example, may be particularly usefulwhen the treatment assembly 1302 is configured to intake all orsubstantially all of the contents of the catcher 1318, including sunkenparticles of abrasive material and/or workpiece material.

Downstream from the intake filter 1400, the treatment assembly 1302 caninclude a chemical coagulation unit 1402 configured to chemicallycoagulate small colloidal particles within the fluid. The chemicalcoagulation unit 1402 can receive a suitable chemical coagulant from thecoagulant supply 1354. Examples of suitable chemical coagulants areprovided below with reference to FIG. 12. The chemical coagulation unit1402 can include one or more mixing chambers (not shown) within whichthe chemical coagulant can be mixed with the fluid batchwise orcontinuously. For example, the chemical coagulation unit 1402 caninclude a first mixing chamber configured for high-speed mixing (e.g.,flash mixing) and a second mixing chamber configured for lower speedmixing downstream from the first chamber. Other structuralconfigurations of the chemical coagulation unit 1402 are also possible.

Interaction between the chemical coagulant and small colloidal particleswithin the fluid can cause the small colloidal particles to coagulateand eventually to form agglomerations (e.g., flocs). The treatmentassembly 1302 can further include a separation unit 1404 downstream fromthe chemical coagulation unit 1402. The separation unit 1404 can beconfigured to receive the fluid from the chemical coagulation unit 1402and to concentrate the agglomerations to form a concentrate (e.g., asludge) and a treated (e.g., clarified) portion of the fluid. Forexample, the separation unit 1404 can be configured to concentrate theagglomerations primarily by filtering, gravity, centrifugation, and/orin another suitable manner. After it is separated, the concentrate canbe moved from the separation unit 1404 to the waste destination 1358 fordisposal (e.g., as solid waste) with or without drying. Alternatively,the concentrate can be recycled.

In some embodiments, the separation unit 1404 is configured toconcentrate the agglomerations primarily by filtering using an in-streamfilter, such as super-micron in-stream filter. Suitable in-streamfilters include disposable super-micron bag filters, among others.Advantageously, this manner of concentrating the agglomerations mayallow the treatment assembly 1302 to be relatively compact while stillachieving relatively high throughput. Disadvantageously, this manner ofconcentrating the agglomerations may necessitate filter replacementand/or other types of maintenance. In other embodiments, the separationunit 1404 can include a settling tank defining a settling chamberconfigured to concentrate the agglomerations primarily by gravity.Advantageously, this manner of concentrating the agglomerations mayrequire relatively little maintenance. Disadvantageously, this manner ofconcentrating the agglomerations may involve the use of relatively largefluidic components (e.g., tanks) in order to achieve acceptablethroughputs. In still other embodiments, the separation unit 1404 can beconfigured to concentrate the agglomerations in another suitable mannerusing other suitable components.

As discussed below with reference to FIG. 12, it can be useful in atleast some cases to use relatively high concentrations of the chemicalcoagulant in the chemical coagulation unit 1402. This may drive theequilibria of coagulation processes toward relatively rapid and completeconversion of small colloidal particles in the fluid intoagglomerations. In these and other cases, it may be useful to removesome or all of the chemical coagulant and/or a concomitant chemicalspecies from the fluid after the coagulation occurs. For example, somechemical coagulants, when present at high concentrations, may cause thefluid to be mildly toxic, corrosive, and/or to have othercharacteristics that would be undesirable within portions of the system1300 outside of the treatment assembly 1302. Many, if not all, chemicalcoagulants used in the chemical coagulation unit 1402 are expected to bepresent in the fluid in the form of ions that contribute to theconcentration of dissolved solids in the fluid. As shown in FIG. 5, thetreatment assembly 1302 can include a dissolved-solids removal unit 1406operably connected to the fluid-recycling loop downstream from theseparation unit 1404. The dissolved-solids removal unit 1406 can beconfigured to decrease the concentration of dissolved solids in thefluid by contacting the fluid and a molecular sieve (e.g., activatedcarbon or a suitable zeolite), by reverse osmosis, by nanofiltration, byion exchange, or in another suitable manner.

In some cases, the dissolved-solids removal unit 1406 separates achemical coagulant from the fluid in a manner that allows the separatedchemical coagulant to be recycled for reuse in the chemical coagulationunit 1402. For example, the dissolved-solids removal unit 1406 can beconfigured to decrease the concentration of dissolved solids in thefluid by reverse osmosis, nanofiltration, and/or ion exchange such thatthe dissolved-solids removal unit 1406 forms a concentrated solution ofdissolved solids including the chemical coagulant. The treatmentassembly 1302 can include a recycling conduit 1408 configured to carrythe concentrated solution of dissolved solids from the dissolved-solidsremoval unit 1406 to the chemical coagulation unit 1402. In other cases,the dissolved-solids removal unit 1406 can separate a chemical coagulantfrom the fluid in a manner that does not involve recycling the separatedchemical coagulant for reuse in the chemical coagulation unit 1402. Forexample, when the dissolved-solids removal unit 1406 is configured todecrease the concentration of dissolved solids in the fluid bycontacting the fluid and a molecular sieve, a cartridge or otherstructure containing the molecular sieve can be configured to bereplaced when it approaches saturation. The used cartridge or otherstructure containing the molecular sieve can then be disposed of assolid waste. Recycling a chemical coagulant can be useful, for example,when the chemical coagulant is relatively expensive, such as when thechemical coagulant includes copper and/or silver.

Some manners of reducing the concentration of dissolved solids in thefluid at the dissolved-solids removal unit 1406 may cause the fluid tobecome prone to leaching material from components of the system 1300downstream from the dissolved-solids removal unit 1406. For example,reverse osmosis may tend to strip out dissolved solids that reduce thisphenomenon as a side effect of reducing the concentration of thechemical coagulant in the fluid. To address this and/or other potentialproblems, the treatment assembly 1302 can include a dosing unit 1410operably connected to the fluid-recycling loop downstream from thedissolved-solids removal unit 1406. The dosing unit 1410 can beconfigured to increase the concentration of dissolved solids in thefluid. For example, the dosing unit 1410 can be configured to draw asupplemental solute from the supplemental solute supply 1356 and addthis supplemental solute to the fluid. The supplemental solute can besodium chloride, potassium chloride, or another compound that does nottend to precipitate at ultrahigh pressures. Although thedissolved-solids removal unit 1406 and the dosing unit 1410 are separatecomponents in the illustrated embodiment, in other embodiments thedissolved-solids removal unit 1406 and the dosing unit 1410 can becombined. For example, an ion-exchange unit can accomplish the functionsof both the dissolved-solids removal unit 1406 and the dosing unit 1410in at least some cases. In still other embodiments, one or both of thedissolved-solids removal unit 1406 and the dosing unit 1410 can beeliminated. Furthermore, the dissolved-solids removal unit 1406 can beconfigured to recover the chemical coagulant without removing other(e.g., smaller) ions from the fluid. For example, the dissolved-solidsremoval unit 1406 can include a nanofiltration membrane that blockspassage of divalent ions (e.g., Cu²⁺) while allowing passage ofmonovalent ions.

The system 1300 can include one or more mechanisms for testing the fluidwithin the fluid-recycling loop. For example, the system 1300 caninclude a dissolved-solids sensor 1412 operably connected to thefluid-recycling loop downstream from the dissolved-solids removal unit1406 and upstream from the pressurizing device 1304. Thedissolved-solids sensor 1412 can be configured to measure an electricalproperty (e.g., electrical conductivity) of the fluid to determine theconcentration of dissolved solids in the fluid. This measurement can beuseful, for example, as input for a feedback loop that controlsoperation of the dosing unit 1410. The system 1300 can further include atesting station 1414 and a turbidity sensor 1416 operably connected tothe fluid-recycling loop downstream from the chemical coagulation unit1402 and upstream from the pressurizing device 1304. The turbiditysensor 1416 can be configured to measure an optical property (e.g.,optical attenuation) of the fluid to determine the turbidity of thefluid, which can correspond to the concentration of small colloidalparticles in the fluid. Downstream from the turbidity sensor 1416 andupstream from the pressurizing device 1304, the system 1300 can includea recirculation valve 1418 configured to divert at least a portion ofthe fluid back through the chemical coagulation unit 1402, such as viathe intake filter 1400. Measurements from the turbidity sensor 1416 canbe useful, for example, as input for a feedback loop that controlsoperation of the recirculation valve 1418. In the illustratedembodiment, the dissolved-solids sensor 1412 and the turbidity sensor1416 are directly connected to the dosing unit 1410 and to the testingstation 1414, respectively. In other embodiments, the dissolved-solidssensor 1412 and/or the turbidity sensor 1416 can be at other suitablepositions within the fluid-recycling loop. In still other embodiments,the dissolved-solids sensor 1412 and/or the turbidity sensor 1416 can beabsent.

With reference to FIGS. 4 and 5 together, the controller 1346 can beoperably associated with various components of the treatment assembly1302. For example, the controller 1346 can be operably associated with apump (not shown) that conveys the fluid into, out of, and/or through thetreatment assembly 1302. The memory 1350 can store computer-readableinstructions (e.g., non-transitory instructions) that, when executed bythe controller 1346 using the processing circuitry 1348, cause thecontroller 1346 to operate the pump so as to maintain a fluid levelwithin the reservoir 1334 above or below a threshold level. This levelcan be monitored, for example using the first level sensor 1342. Inaddition or alternatively, the instructions, when executed by thecontroller 1346 using the processing circuitry 1348, can cause thecontroller 1346 to operate the pump so as to maintain a fluid levelwithin the catcher 1318 above or below a threshold level. This level canbe monitored, for example using the second level sensor 1344.Furthermore, the controller 1346 can be operably associated with thedissolved-solids sensor 1412 and with the dosing unit 1410. Theinstructions, when executed by the controller 1346 using the processingcircuitry 1348, can cause the controller 1346 to operate the dosing unit1410 so as to increase the concentration of dissolved solids in thefluid in response to an indication from the dissolved-solids sensor 1412that the concentration of dissolved solids in the fluid is below athreshold. In this way, for example, the controller 1346 can at leastpartially prevent the fluid from reaching the pressurizing device 1304with an unacceptably low concentration of dissolved solids. Similarly,the controller 1346 can be operably associated with the turbidity sensor1416 and with the recirculation valve 1418. The instructions, whenexecuted by the controller 1346 using the processing circuitry 1348, cancause the controller 1346 to operate the recirculation valve 1418 so asto divert the fluid from a course through the fluid-recycling loop inresponse to an indication from the turbidity sensor 1416 that theturbidity of the fluid is above a threshold. In this way, for example,the controller 1346 can at least partially prevent the fluid fromreaching the pressurizing device 1304 with an unacceptably highconcentration of small colloidal particles.

FIG. 6 is a partially schematic perspective view of a waterjet system1500 in accordance with an embodiment of the present technology havingthe third arrangement (FIG. 3) and including a treatment assembly 1502configured for electrocoagulation. The system 1500 can be generallysimilar to the system 1300 shown in FIG. 4. As shown in FIG. 6, thetreatment assembly 1502 can be operably connected to a combination ofsupport elements different than the combination of support elements towhich the treatment assembly 1302 of the system 1300 shown in FIG. 4 isconnected. In particular, the treatment assembly 1502 can be operablyconnected to a power supply 1504, a container 1506, and the wastedestination 1358, all shown schematically. FIG. 7 is a block diagramillustrating several interconnected components of the system 1500. Aswith the treatment assembly 1302 of the system 1300 shown in FIG. 4, thetreatment assembly 1502 can include the intake filter 1400, thedissolved-solids removal unit 1406, the dissolved-solids sensor 1412,the testing station 1414, the turbidity sensor 1416, and therecirculation valve 1418.

Downstream from the intake filter 1400 and operably connected to thepower supply 1504, the treatment assembly 1502 can include anelectrocoagulation unit 1600 configured to electrocoagulate smallcolloidal particles within the fluid. The power supply 1504 can beconfigured to supply electrical power to electrodes (not shown in FIGS.6 and 7) within the electrocoagulation unit 1600. The controller 1346can be operably associated with the power supply 1504 to controloperation of the electrocoagulation unit 1600. The electrocoagulationunit 1600 and the power supply 1504 are discussed in further detailbelow with reference to FIG. 8. While the fluid passes through theelectrocoagulation unit 1600, small colloidal particles within the fluidcan begin to coagulate. One or more reactions that occur within theelectrocoagulation unit 1600 may generate gas (e.g., hydrogen gas) thatforms bubbles within the fluid. Downstream from the electrocoagulationunit 1600, the treatment assembly 1502 can include a vent 1602configured to allow this gas to exit the fluid. The vent 1602, forexample, can be a port that discharges to the atmosphere or, as shown inthe illustrated embodiment, a port that discharges to the container1506.

After passing through the vent 1602, the fluid can travel into aseparation unit 1604 configured to separate coagulated small colloidalparticles from the fluid into a concentrate (e.g., a sludge). In theillustrated embodiment, the separation unit 1604 includes a settlingchamber 1606 and a post-settling filter 1608 downstream from thesettling chamber 1606. Within the settling chamber 1606, the coagulatedsmall colloidal particles within the fluid can coalesce intoagglomerations (e.g., flocs) and eventually sink to form theconcentrate. As described below with reference to FIG. 9, theconcentrate can be collected from a lower portion of the settlingchamber 1606 after it settles. The post-settling filter 1608 can beuseful to reduce or eliminate egress of stray agglomerations that do notsettle within the settling chamber 1606. In some embodiments, thepost-settling filter 1608 is nominally rated for removal of at least 90%of particles larger than a suitable threshold size (e.g., 0.5 micron,0.75 micron, or 1 micron). For example, the post-settling filter 1608can be configured to remove all or substantially all agglomerationslarger than the threshold size from the fluid. In other embodiments, thepost-settling filter 1608 can have other suitable specifications.

Although passing through the treatment assembly 1502 once is notexpected to cause a significant increase in the concentration ofdissolved solids in the fluid, multiple passes through the treatmentassembly 1502 may have a cumulative effect that increases theconcentration of dissolved solids in the fluid to an unacceptably highlevel. As discussed above, high concentrations of dissolved solids cancause undesirable precipitation of solids at ultrahigh pressures. Toaddress this problem, the treatment assembly 1502 can include thedissolved-solids removal unit 1406 downstream from the separation unit1604. In general, the degree to which electrocoagulation increases theconcentration of dissolved solids in the fluid may be less than thedegree to which chemical coagulation increases the concentration ofdissolved solids in the fluid. Thus, it is expected that only limitedremoval of dissolved solids by the dissolved-solids removal unit 1406may be needed. In fact, in some cases, the dissolved-solids removal unit1406 can be eliminated without significantly undermining performance ofthe system 1500. In other cases, the dissolved-solids removal unit 1406can be configured to treat only a portion of the fluid flowing throughthe fluid-recycling loop.

In the illustrated embodiment, the dissolved-solids removal unit 1406 ispositioned in-line with a primary flowpath through the fluid-recyclingloop. In other embodiments, the dissolved-solids removal unit 1406 canbe positioned along a branch of the fluid-recycling loop separate fromthe primary flowpath. For example, the system 1500 can include adiverter (not shown) configured to route a portion of the fluid throughthe dissolved-solids removal unit 1406 while a remaining portion of thefluid bypasses the dissolved-solids removal unit 1406. The controller1346 can be operably associated with the diverter. In this case, thememory 1350 can store instructions that, when executed by the controller1346 using the processing circuitry 1348, cause the controller 1346 tooperate the diverter so as to control the relative amount of the fluidrouted through the dissolved-solids removal unit 1406. Alternatively orin addition, the dissolved-solids removal unit 1406 can be duty cycledor otherwise controlled so as to remove only a portion of the dissolvedsolids in the fluid flowing through the primary flowpath or a branchthereof. In this case, the memory 1350 can store instructions that, whenexecuted by the controller 1346 using the processing circuitry 1348,cause the controller 1346 to operate the dissolved-solids removal unit1406 so as to maintain a concentration of dissolved solids in the fluidwithin a predetermined range.

FIG. 8 is a cross-sectional profile view of the electrocoagulation unit1600 of the treatment assembly 1502. The electrocoagulation unit 1600can include a housing 1700 and an electrocoagulation chamber 1702 withinthe housing 1700. The electrocoagulation unit 1600 can further includeone or more first electrodes 1704 (individually identified as firstelectrodes 1704 a-d) and one or more second electrodes 1706(individually identified as second electrodes 1706 a-c) alternatinglydisposed within the electrocoagulation chamber 1702. The individualfirst electrodes 1704 and adjacent individual second electrodes 1706 canform electrode pairs individually defining upwardly extending flowpaths1708 (individually identified as flowpaths 1708 a-f) therebetween. Thefirst and second electrodes 1704, 1706 can be operably connected toopposite terminals of the power supply 1504 and configured to beelectrically charged with opposite polarities at any given time. In someembodiments, the power supply 1504 is configured to deliver directcurrent (e.g., at 36 volts and 30 amps or another suitable level) withor without polarity switching. In other embodiments, the power supply1504 is configured to deliver alternating current. In response to theapplied charge, adjacent first and second electrodes 1704, 1706 canundergo an electrolysis reaction that generates ions and, in at leastsome cases, electrolysis products within the fluid as it flows throughthe flowpaths 1708. Different electrode materials can be used to causedifferent reactions, which may tend to promote coagulation of differenttypes of small colloidal particles. The materials of the first andsecond electrodes 1704, 1706 can be the same or different. In oneexample, the first and second electrodes 1704, 1706 are made primarilyor entirely of aluminum. In another example, the first and secondelectrodes 1704, 1706 are made primarily or entirely of mild steel.Other materials and combinations are also possible.

The first and second electrodes 1704, 1706 can be shaped to have largesurface areas in contact with the flowpaths 1708. For example, the firstand second electrodes 1704, 1706 can be shaped as flat or non-flat(e.g., ridged) plates. The thickness of such plates can be, for example,from 0.15 centimeter to 0.45 centimeter, such as about 0.32 centimeter.Spacing between adjacent first and second electrodes 1704, 1706 can be,for example, from 2 cm to 10 cm, such as about 5 centimeters. Theelectrocoagulation unit 1600 can be configured to allow the first andsecond electrodes 1704, 1706 to be replaced conveniently. Replacement ofthe first and second electrodes 1704, 1706 can occur, for example, afterthe electrocoagulation unit 1600 operates for a certain amount of time.The first and second electrodes 1704, 1706 can also be replaced tochange the electrocoagulation reactions so as to better suit thecharacteristics of a fluid being treated. For example, when the system1300 is used to process different types of materials and/or used withdifferent types of abrasive materials, different types of smallcolloidal particles may be generated. When fluid containing theseparticles is treated, the first and second electrodes 1704, 1706 can beselected to be of a material type that causes an electrolytic reactionwell suited for coagulating the type of small colloidal particles beinggenerated.

The electrocoagulation unit 1600 can include an inlet manifold 1710extending through a series of holes 1714 (one identified in FIG. 3) inlower portions of the first and second electrodes 1704, 1706. The inletmanifold 1710 can include a series of laterally distributed openings1716 (one identified in FIG. 3) and an end cap 1712 and can beconfigured to distribute fluid through the openings 1716 as the fluidenters the electrocoagulation chamber 1702. This can cause relativelyequal portions of the fluid to be routed along the respective flowpaths1708. To avoid creating short circuits, the inlet manifold 1710 and anysupport structures (e.g., spacers, clamps, etc.) (not shown) in contactwith the first and second electrodes 1704, 1706 can be electricallynonconductive or otherwise electrically isolated from the first andsecond electrodes 1704, 1706 and from the flowpaths 1708. Below theinlet manifold 1710, a lower portion of the electrocoagulation chamber1702 can be tapered with a horizontal cross-sectional area thatdecreases toward a first concentrate outlet 1718 of the separation unit1604. Depending on operation of the electrocoagulation unit 1600, someconcentrate may collect in the lower portion of the electrocoagulationchamber 1702. This concentrate can be removed from theelectrocoagulation unit 1600 continuously or non-continuously (e.g.,periodically).

In the illustrated embodiment, the first and second electrodes 1704,1706 and the flowpaths 1708 are vertically oriented and theelectrocoagulation unit 1600 includes a first fluid outlet 1720extending from an upper portion of the electrocoagulation chamber 1702.In other embodiments, the first and second electrodes 1704, 1706 and theflowpaths 1708 can be diagonally oriented, or have other suitableorientations and/or the first fluid outlet 1720 can have other suitablepositions. Flowing the fluid upward during electrocoagulation mayincrease the overall percentage of small colloidal particles in fluidentering the electrocoagulation unit 1600 that are adequately coagulatedby the time the fluid exits the electrocoagulation unit 1600. Forexample, the fluid may flow upward at a steady-state flowrate that tendsto cause large agglomerations of electrocoagulated small colloidalparticles to remain suspended within the flowpaths 1708 for prolongedperiods of time. While suspended, these agglomerations may serve aseffective collectors of additional small colloidal particles. Forcesacting on the suspended agglomerations include drag from the flowingfluid, gravity, and buoyancy from bubbles of gas that may form duringelectrocoagulation and become attached to surfaces of the agglomerationsover time. These forces may change over time as the agglomerationsincrease in size and accumulate more surface bubbles. Given the balanceof these forces, the steady-state flowrate of the fluid through theelectrocoagulation unit 1600, the height of the flowpaths 1708, and/orother factors can be selected to cause the agglomerations to remainsuspended for as long as possible. The heights of the flowpaths 1708 canbe for example, from 130 centimeters to 230 centimeters, such as about182 centimeters. The individual first and second electrodes 1704, 1706and/or the electrocoagulation chamber 1702 can have greater heights thanwidths. For example, the individual first and second electrodes 1704,1706 and/or the electrocoagulation chamber 1702 can have heights from 4times to 14 times their widths, such as about 9 times their widths.After being suspended, the agglomerations can settle to form concentrateor exit the electrocoagulation unit 1600 with the fluid via the firstfluid outlet 1720.

FIG. 9 is a partially cross-sectional profile view of the separationunit 1604 of the treatment assembly 1502. In the illustrated embodiment,the vent 1602 is a tee junction with a first branch 1800 that extendsupward for venting gas and a second branch 1802 that extends downwardfor carrying the fluid. In other embodiments, the vent 1602 can haveanother suitable form. Downstream from the vent 1602, the treatmentassembly 1502 can include a fluid-delivery conduit 1804 extendingdownward toward a fluid inlet 1806 of the settling chamber 1606. Thefluid-delivery conduit 1804 can be at least partially serpentine. Thiscan increase the length of the passage through which the fluid flows andincrease turbulence in the fluid, both of which may tend to increase thedegree to which gas bubbles are eliminated from the fluid.Alternatively, the fluid-delivery conduit 1804 can be straight or haveanother suitable shape. The fluid inlet 1806 can open into a lowerportion of the settling chamber 1606. Similar to the lower portion ofthe electrocoagulation chamber 1702 (FIG. 8), the lower portion of thesettling chamber 1606 can be tapered with a horizontal cross-sectionalarea that decreases toward a second concentrate outlet 1810 extendingfrom the lower portion of the settling chamber 1606. Operably connectedto the second concentrate outlet 1810, the treatment assembly 1502 caninclude a concentrate-removal element 1812 having a concentrate-removalvalve 1814 and a concentrate-removal port 1816 downstream from theconcentrate-removal valve 1814. The concentrate-removal valve 1814 canbe configured to open and close a fluidic connection between theconcentrate-removal port 1816 and the second concentrate outlet 1810and/or to otherwise control a flowrate of concentrate through the secondconcentrate outlet 1810.

As shown in FIG. 9, the settling chamber 1606 can contain aconcentrate-to-clarified-fluid interface 1822. Extending from an upperportion of the settling chamber 1606, the separation unit 1604 caninclude a second fluid outlet 1824 configured to allow the fluid, in aclarified state, to exit the settling chamber 1606 above the interface1822. When the fluid is introduced into the settling chamber 1606 belowthe interface 1822, it is expected to migrate upward through a settledvolume of concentrate toward the second fluid outlet 1824. In this way,remaining uncoagulated small colloidal particles within the fluid maytend to become incorporated into and remain with the settled volume ofconcentrate, thereby further increasing the percentage of smallcolloidal particles removed from the fluid during treatment. Any gasbubbles that enter the settling chamber 1606 with the fluid mayundesirably tend to carry concentrate from the settled volume ofconcentrate upward toward the second fluid outlet 1824. Separating thesebubbles from the fluid as it flows through the fluid-delivery conduit1804 and venting the gas that forms the bubbles via the vent 1602 canreduce or eliminate this problem. In at least some cases, the fluid, ina clarified state, is discharged from the settling chamber 1606 withouta filter to hold back concentrate.

With reference to FIGS. 6 and 9 together, the system 1500 can include athird level sensor 1826 disposed at least partially within the settlingchamber 1606 and configured to detect the level of the interface 1822.The third level sensor 1826 and the concentrate-removal valve 1814 canbe operably associated with the controller 1346. The memory 1350 canstore instructions that, when executed by the controller 1346 using itsprocessing circuitry 1348, cause the controller 1346 to operate theconcentrate-removal valve 1814 so as to maintain the interface 1822above the fluid inlet 1806 and below the second fluid outlet 1824.Alternatively or in addition, the level of the interface 1822 can bemonitored and maintained by operating the concentrate-removal valve 1814manually. The concentrate-removal element 1812 can be configured toallow the concentrate to be fluidically separated from the settlingchamber 1606 before being subjected to further processing. For example,the concentrate-removal element 1812 can be configured to allow theconcentrate to be fluidically separated from the settling chamber 1606without filtering. In some embodiments, the concentrate-removal port1816 includes an appendix 1828 configured to collect concentrate whenthe concentrate-removal valve 1814 is opened and to be removed from theconcentrate-removal element 1812 after the concentrate-removal valve1814 is closed. Once removed from the concentrate-removal element 1812,the appendix 1828 can be used to transport the concentrate to a dryingtray 1830 where the concentrate can be dried before disposal. In otherembodiments, the concentrate-removal element 1812 can be configured toallow the concentrate to be removed in another suitable manner.

Selected Examples of Methods for Operating Waterjet Systems

FIG. 10 is a flow chart illustrating a method 1900 for operating thewaterjet system 1000 shown in FIG. 1 in accordance with an embodiment ofthe present technology. With reference to FIGS. 1 and 10 together, themethod 1900 can include drawing fluid from the fluid source 1004 (block1902) into the reservoir 1002 and then into the pressurizing device1006. Next, the method 1900 can include pressurizing the fluid (block1904) to a pressure suitable for waterjet processing using thepressurizing device 1006. In at least some cases, the pressurizingdevice 1006 is not a direct-drive plunger pump in the context of themethod 1900. The fluid can then be fed into the cutting head 1008 (block1906) and used to form a jet, such as by passing the fluid through asuitable orifice. Particles of abrasive material (e.g., garnet) can beincorporated into the jet (block 1908) and the jet can be directedtoward a workpiece (block 1910). After impacting the workpiece, the jetcan diffuse into a fluid pool within the catcher 1010 (block 1912).

Impacting the workpiece and/or the fluid pool can cause the particles ofabrasive material within the jet to break apart into small fragmentsthat then disperse within the fluid pool as small colloidal particles.The level of fluid within the fluid pool can be monitored and, if thelevel is above a threshold level, fluid from the fluid pool can be fedinto the treatment assembly 1012 (block 1914). Within the treatmentassembly 1012, the fluid can be treated (block 1916), such as by one ofthe methods described below with reference to FIGS. 12 and 13. Beforebeing treated, the fluid may be unsuitable for disposal. For example,the fluid may have a characteristic, such as general characteristic(e.g., turbidity) and/or a specific characteristic (e.g., aconcentration of a specific substance), that falls outside aspecification for acceptable discharges into a municipal sewage system.Treating the fluid can change this characteristic so that the fluidfalls inside the specification. After the fluid is treated, the method1900 can include disposing of the fluid (block 1918), such as by routingthe fluid to the waste destination 1014.

FIG. 11 is a flow chart illustrating a method 2000 for operating thewaterjet system 1100 shown in FIG. 2 in accordance with an embodiment ofthe present technology. With reference to FIGS. 2 and 11 together, themethod 2000 can include drawing fluid from the fluid source 1004 (block2002), feeding the fluid into the treatment assembly 1012 (block 2004),and then treating the fluid (block 2006) using the treatment assembly1012. Next, the method 2000 can include feeding the fluid into thereservoir 1002 (block 2008) and drawing the fluid from the reservoir1002 (block 2010) when needed. The fluid drawn from the reservoir 1002can be pressurized (block 2012) to a pressure suitable for waterjetprocessing using the pressurizing device 1006. In at least some cases,the pressurizing device 1006 is a direct-drive plunger pump in thecontext of the method 2000. Before being treated, the fluid may have aconcentration of small colloidal particles that would adversely affectthe pressurizing device 1006. Treating the fluid can decrease theconcentration of small colloidal particles to a more suitable level foruse in the pressurizing device 1006.

After being pressurized, the fluid can be fed into the cutting head 1008(block 2014) and used to form a jet, such as by passing the fluidthrough a suitable orifice. Particles of abrasive material (e.g.,garnet) can be incorporated into the jet (block 2016) and the jet can bedirected toward a workpiece (block 2018). After impacting the workpiece,the jet can diffuse into a fluid pool within the catcher 1010 (block2020). Impacting the workpiece and/or the fluid pool can cause theparticles of abrasive material within the jet to break apart into smallfragments that then disperse within the fluid pool as small colloidalparticles. The level of fluid within the fluid pool can be monitoredand, if the level is above a threshold level, fluid from the fluid poolcan be disposed of (block 2022), such as by routing the fluid to thewaste destination 1014.

FIG. 12 is a flow chart illustrating a method 2100 for operating thesystem 1300 shown in FIG. 4 in accordance with an embodiment of thepresent technology. With reference to FIGS. 4, 5 and 12 together, themethod 2100 can include drawing fluid from the reservoir 1334 (block2102) into the pressurizing device 1304. Next, the method 2100 caninclude pressurizing the fluid (block 2104) to a pressure suitable forwaterjet processing. In at least some cases, the pressurizing device1304 is a direct-drive plunger pump in the context of the method 2100.The fluid can then be fed into the cutting head 1306 (block 2106) andused to form a jet, such as by passing the fluid through a suitableorifice. Particles of abrasive material (e.g., garnet) can beincorporated into the jet (block 2108) and the jet can be directedtoward a workpiece (block 2110). After impacting the workpiece, the jetcan diffuse into a fluid pool within the catcher 1318 (block 2112).Impacting the workpiece and/or the fluid pool can cause the particles ofabrasive material within the jet to break apart into small fragmentsthat then disperse within the fluid pool as small colloidal particles.

The level of fluid within the fluid pool can be monitored using thesecond level sensor 1344 and, if the level is above a threshold level,fluid from the fluid pool can be fed into the treatment assembly 1302(block 2114). Treating the fluid can begin with intake filtering (block2116) using the intake filter 1400. Next, small colloidal particles inthe fluid can be chemically coagulated (block 2118) using the chemicalcoagulation unit 1402. As discussed above with reference to FIG. 5, thechemical coagulation unit 1402 can include a first mixing chamberconfigured for high-speed mixing (e.g., flash mixing) and a secondmixing chamber configured for lower speed mixing downstream from thefirst chamber. The average residence time of the fluid in the firstchamber can be relatively short (e.g., less than 1 minute) so as toevenly distribute the chemical coagulant within the fluid without undueshearing of newly formed agglomerations of small colloidal particles.The average residence time of the fluid in the second chamber can belonger (e.g., greater than 1 minute) to promote further coagulation ofthe small colloidal particles in a low-shear environment. In at leastsome cases, at least 50% by count of all small colloidal particles ofsieve diameter within a range from 0.005 to 0.2 microns in a givenvolume of the fluid are coagulated. For example, at least 90% by countof all of the submicron fragments of sieve diameter within a range from0.005 to 0.2 microns in a given volume of the fluid can be coagulated.

The chemical coagulant used to coagulate the small colloidal particlesin the fluid can be a salt that is soluble in the fluid at roomtemperature and neutral pH to form a metallic ion and a counter ion. Inat least some cases, the chemical coagulant includes iron, tin, copper,and/or silver. In particular cases, the chemical coagulant includescopper. For example, the chemical coagulant can be copper(II) chlorideor copper(II) sulfate. Copper(II) sulfate, in particular, has been foundto rapidly and effectively coagulate small colloidal particles of garnetin water with few, if any, undesirable side effects. Certain otherchemical coagulants when used in this context have been found,undesirably, to significantly change the pH of the fluid, tosignificantly increase in the concentration dissolved solids in thefluid, and/or to form excessively voluminous concentrates. Theconcentration of the metallic ion in the fluid after adding the chemicalcoagulant can be relatively high. For example, the small colloidalparticles within the fluid can be coagulated while a molar concentrationof the metallic ion in the fluid is greater than 0.1 millimolar. In somecases, the small colloidal particles within the fluid are coagulatedwhile the molar concentration of the metallic ion in the fluid isgreater than 0.2 millimolar, such as within a range from 0.2 millimolarto 0.4 millimolar. Relatively high concentrations of the metallic ionmay expedite coagulation. Lower concentrations of the metallic ion canalso be used, such as when the speed at which the coagulation occurs isof low importance.

In at least some embodiments of the present technology, when smallcolloidal particles in a fluid include garnet, the chemical coagulantadded to the fluid is a salt soluble in the fluid to form a metallic ionof a metal lower than sodium on the electrochemical series in itsstandard presentation (i.e., with lithium toward the top and gold towardthe bottom). Metals lower than sodium on the electrochemical seriesinclude iron, tin, copper, and silver. These and other metals may bebound to various counter ions, such as halogens (e.g., fluorine,chlorine, bromine, or iodine), nitrate, or sulfate, among others. Itshould be understood that the chemical coagulants (including specificchemical coagulants and classes of chemical coagulants) described aboveare not exclusive. While these chemical coagulants may be well suitedfor use in some embodiments of the present technology, in otherembodiments, using different chemical coagulants may be advantageous.

After adding the chemical coagulant, the method 2100 can includeconcentrating the coagulated small colloidal particles (block 2120) intoa volume of concentrate (e.g., sludge) using the separation unit 1404.This, in turn, can decrease a concentration of the coagulated smallcolloidal particles in the remaining fluid, thereby forming a clarifiedportion of the fluid. Concentrating the coagulated small colloidalparticles can be carried out, for example, by filtration, gravity,centrifugation, or a combination thereof. In a particular example, thefluid is filtered using a super-micron filter that traps the coagulatedsmall colloidal particles. A primary flowpath for the fluid through thetreatment assembly 1302 may pass through the super-micron filter suchthat concentrate held in the super-micron filter acts as a trap forgathering additional small colloidal particles that were not previouslycoagulated. As another example, the fluid may be held in a chamber toallow the coagulated small colloidal particles to settle or float due togravity. The resulting volume of concentrate can then be collected byskimming, dredging, or a combination thereof.

After concentrating the coagulated small colloidal particles, the method2100 can include separating a clarified portion of the fluid from theconcentrate (block 2122). The concentration of dissolved solids in theclarified portion of the fluid can then be decreased (block 2124). Thiscan include recovering an excess portion of the chemical coagulant inthe fluid for recycling to the chemical coagulation unit 1402 or fordisposal. For example, dissolved solids can be removed from the fluid byreverse osmosis, nanofiltration, ion exchange or another suitabletechnique to form a concentrated solution of a metallic ion of thechemical coagulant. Once formed, this concentrated solution can berouted to the chemical coagulation unit 1402 for reuse or routed to thewaste destination 1358 for disposal. Alternatively or in addition, thefluid can be contacted with a molecular sieve (e.g., activated carbon)to decrease a concentration of the metallic ion in the fluid. Afterreducing the concentration of dissolved solids in the fluid, the method2100 can include measuring the concentration of dissolved solids in thefluid using the dissolved-solids sensor 1412, such as by measuring anelectrical property of the fluid. The concentration of dissolved solidsin the fluid can be increased based on the measured concentration ofdissolved solids. For example, if the concentration of dissolved solidsin the fluid is below a threshold, supplemental solute from thesupplemental solute supply 1356 can be added to the fluid (block 2126)until the concentration of dissolved solids in the fluid exceeds a highthreshold.

The method 2100 can further include measuring a turbidity of the fluidusing the turbidity sensor 1416, such as by measuring an opticalproperty of the fluid. If the turbidity measurement is too high (e.g.,higher than a turbidity known to be detrimental to the life of seals inthe pressurizing device 1304) the fluid can be diverted from a coursethrough the treatment assembly 1302. For example, the fluid can berecirculated through the chemical coagulation unit 1402 via the intakefilter 1400. If the turbidity measurement is acceptable, the fluid canbe fed into the reservoir 1334 (block 2128) where it can wait to bedrawn again into the pressurizing device 1304. The level of the fluidwithin the reservoir 1334 can be monitored using the first level sensor1342 and, if the level is below a threshold level, makeup fluid (e.g.,municipal water) can be added (block 2130). If the level is above thethreshold level or if adding the makeup fluid causes the level to beabove the threshold level, addition of makeup fluid can slow, stop, orremain slowed or stopped.

FIG. 13 is a flow chart illustrating a method 2200 for operating thesystem 1500 shown in FIG. 6 in accordance with an embodiment of thepresent technology. With reference to FIGS. 6, 7 and 13 together, themethod 2200 can include drawing fluid from the reservoir 1334 (block2202) into the pressurizing device 1304. Next, the method 2200 caninclude pressurizing the fluid (block 2204) to a pressure suitable forwaterjet processing. In at least some cases, the pressurizing device1304 is a direct-drive plunger pump in the context of the method 2200.The fluid can then be fed into the cutting head 1306 (block 2206) andused to form a jet, such as by passing the fluid through a suitableorifice. Particles of abrasive material (e.g., garnet) can beincorporated into the jet (block 2208) and the jet can be directedtoward a workpiece (block 2210). After impacting the workpiece, the jetcan diffuse into a fluid pool (block 2212) within the catcher 1318.Impacting the workpiece and/or the fluid pool can cause the particles ofabrasive material within the jet to break apart into small fragmentsthat then disperse within the fluid pool as small colloidal particles.

The level of fluid within the fluid pool can be monitored using thesecond level sensor 1344 and, if the level is above a threshold level,fluid from the fluid pool can be fed into the treatment assembly 1502(block 2214). Treating the fluid can begin with intake filtering (block2216) using the intake filter 1400. Next, small colloidal particles inthe fluid can be electrocoagulated (block 2218). As discussed above withreference to FIG. 8, electrocoagulating the small colloidal particlescan include flowing the fluid upward along one or more of the flowpaths1708. In some embodiments, the fluid is flowed at a steady-stateflowrate from 1 to 1.5 gallons per minute causing the fluid to moveupward along one or more of the flowpaths 1708 at a speed of 4 to 6inches per minute. The fluid can have an average residence time betweenthe first and second electrodes 1704, 1706, for example, from 12 minutesto 18 minutes. In other embodiments, the fluid can be flowed at anothersuitable rate. In comparison to the average residence time of the fluidbetween the first and second electrodes 1704, 1706, the averageresidence time of the electrocoagulated colloidal particles between thefirst and second electrodes 1704, 1706 may be the about same, lower(e.g., due to the buoyancy of associated bubbles of gas), or higher(e.g., due to settling). After exiting the electrocoagulation unit 1600,gas produced in association with the electrocoagulation can be vented(block 2220) and the fluid can be fed into the settling chamber 1606(block 2222). In some embodiments, at least 99% of the total amount ofgas formed at steady state is vented. In other embodiments, a lesseramount of gas may be vented. The fluid can be introduced into thesettling chamber 1606 via the fluid inlet 1806 below the interface 1822.

Within the settling chamber 1606, the electrocoagulated small colloidalparticles can be concentrated to form a settled volume of concentrate(block 2224) and the fluid, in a clarified state, can be separated fromthe settled volume of concentrate (block 2226). For example, theelectrocoagulated colloidal particles can be settled by gravity into thelower portion of the settling chamber 1606. The fluid, in a clarifiedstate, can be output from the upper portion of the settling chamber 1606via the second fluid outlet 1824 above the interface 1822. The level ofthe interface 1822 within the settling chamber 1606 can be monitoredusing the third level sensor 1826 and, if the level is above a thresholdlevel, concentrate can be removed from the settled volume of concentrate(block 2228). If the level is below the threshold level or if removingthe concentrate causes the level to be below the threshold level,removal of the concentrate can slow or stop or remain slowed or stopped.The concentrate can removed from the lower portion of the settlingchamber 1606 at a rate that causes the fluid inlet 1806 to remain belowthe interface 1822 and the catcher outlet 1332 to remain above theinterface 1822. This rate at which the concentrate is removed, forexample, can be a continuous rate or a non-continuous (e.g., periodic)rate.

After exiting the settling chamber 1606, the fluid can be subjected topost-settling filtering (block 2230) using the post-settling filter1608. Next, the concentration of dissolved solids in the fluid can bedecreased (block 2232) using the dissolved-solids removal unit 1406. Themethod 2200 can further include measuring a turbidity of the fluid usingthe turbidity sensor 1416, such as by measuring an optical property ofthe fluid. If the turbidity measurement is too high (e.g., higher than aturbidity known to be detrimental to the life of seals in thepressurizing device 1304) the fluid can be diverted from a coursethrough the treatment assembly 1502. For example, the fluid can berecirculated through the electrocoagulation unit 1600 via the intakefilter 1400. If the turbidity measurement is acceptable, the fluid canbe fed into the reservoir 1334 (block 2234) where it can wait to bedrawn again into the pressurizing device 1304. The level of the fluidwithin the reservoir 1334 can be monitored using the first level sensor1342 and, if the level is below a threshold level, makeup fluid (e.g.,municipal water) can be added (block 2236). If the level is above thethreshold level or if adding the makeup fluid causes the level to beabove the threshold level, addition of makeup fluid can slow, stop, orremain slowed or stopped.

With reference to FIGS. 3-7, 12 and 13 together, the methods 2100, 2200can include circulating fluid (e.g., as process fluid, contaminatedfluid, clarified fluid, etc.) within a fluid-recycling loopcorresponding to the fluid-recycling loop 1202 shown in FIG. 3.Pressurizing the fluid in the methods 2100, 2200 can occur at the firstportion 1202 a of the fluid-recycling loop 1202. Feeding the fluid intothe cutting head 1306, forming the fluid into a jet, incorporatingabrasive material into the jet, and directing the jet toward a workpiecein the methods 2100, 2200 can occur at the second portion 1202 b of thefluid-recycling loop 1202. Treating the fluid and measuring theconcentration of dissolved solids in the fluid in the methods 2100, 2200can occur at the third portion 1202 c of the fluid-recycling loop 1202.Measuring the turbidity of the fluid and feeding the fluid into thereservoir 1334 in the methods 2100, 2200 can occur at the fourth portion1202 d of the fluid-recycling loop 1202. The methods 2100, 2200 maycause relatively little fluid loss. Thus, makeup fluid may be added at arelatively low rate, such as a steady-state flowrate less than 2% of anoverall steady-state flowrate of the fluid through the fluid-recyclingloop 1202. The methods 2100, 2200 can include reducing a turbidity of afluid a relatively large amount, such as from a first turbidity greaterthan 1000 nephelometric turbidity units to a second turbidity less than5 nephelometric turbidity units, such as less than 3 nephelometricturbidity units, or, in some cases, less than 1 nephelometric turbidityunit. In contrast, with reference to FIG. 10, the method 1900 caninclude reducing a turbidity of a fluid a relatively small amount, suchas from a first turbidity within a range from 2 nephelometric turbidityunits to 10 nephelometric turbidity units to a second turbidity lessthan 2 nephelometric turbidity units, such as less than 1 nephelometricturbidity unit, or, in some cases, less than 0.5 nephelometric turbidityunit. Other specifications may apply in other embodiments.

CONCLUSION

This disclosure is not intended to be exhaustive or to limit the presenttechnology to the precise forms disclosed herein. Although specificembodiments are disclosed herein for illustrative purposes, variousequivalent modifications are possible without deviating from the presenttechnology, as those of ordinary skill in the relevant art willrecognize. Accordingly, this disclosure and associated technology canencompass other embodiments not expressly shown or described herein. Insome cases, well-known structures and functions have not been shown ordescribed in detail to avoid unnecessarily obscuring the description ofembodiments of the present technology. Although steps of methods may bepresented herein in a particular order, in alternative embodiments, thesteps may have another suitable order. Similarly, certain aspects of thepresent technology disclosed in the context of particular embodimentscan be combined or eliminated in other embodiments. Furthermore, whileadvantages associated with certain embodiments may have been disclosedin the context of those embodiments, other embodiments can also exhibitsuch advantages, and not all embodiments need necessarily exhibit suchadvantages or other advantages disclosed herein to fall within the scopeof the present technology.

Certain aspects of the present technology may take the form ofcomputer-executable instructions, including routines executed by acontroller or other data processor. In some embodiments, a controller orother data processor is specifically programmed, configured, orconstructed to perform one or more of these computer-executableinstructions. Furthermore, some aspects of the present technology maytake the form of data (e.g., non-transitory data) stored or distributedon computer-readable media, including magnetic or optically readable orremovable computer discs as well as media distributed electronicallyover networks. Accordingly, data structures and transmissions of dataparticular to aspects of the present technology are encompassed withinthe scope of the present technology. The present technology alsoencompasses methods of both programming computer-readable media toperform particular steps and executing the steps.

The methods disclosed herein include and encompass, in addition tomethods of making and using the disclosed apparatuses and systems,methods of instructing others to make and use the disclosed apparatusesand systems. For example, a method in accordance with a particularembodiment includes pressurizing a fluid to a pressure greater than30,000 psi, forming the fluid into a jet, directing the jet toward aworkpiece, and treating a resulting fluid. A method in accordance withanother embodiment includes instructing such a method.

Throughout this disclosure, the singular terms “a,” “an,” and “the”include plural referents unless the context clearly indicates otherwise.Similarly, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the terms “comprising” and the like are used throughout this disclosureto mean including at least the recited feature(s) such that any greaternumber of the same feature(s) and/or one or more additional types offeatures are not precluded. Directional terms, such as “upper,” “lower,”“front,” “back,” “vertical,” and “horizontal,” may be used herein toexpress and clarify the relationship between various elements. It shouldbe understood that such terms do not denote absolute orientation.Reference herein to “one embodiment,” “an embodiment,” or similarformulations means that a particular feature, structure, operation, orcharacteristic described in connection with the embodiment can beincluded in at least one embodiment of the present technology. Thus, theappearances of such phrases or formulations herein are not necessarilyall referring to the same embodiment. Furthermore, various particularfeatures, structures, operations, or characteristics may be combined inany suitable manner in one or more embodiments.

I/We claim:
 1. A method, comprising: pressurizing a fluid to a pressuregreater than 30,000 psi at a first portion of a fluid-recycling loop;forming the fluid into a jet and directing the jet toward a workpiecesuch that the jet impacts the workpiece and abrasive particles withinthe jet break apart into submicron fragments at a second portion of thefluid-recycling loop, the second portion being downstream from the firstportion during a pass through the fluid-recycling loop originating atthe first portion; and treating the fluid at a third portion of thefluid-recycling loop, the third portion being downstream from the secondportion and upstream from the first portion during the pass through thefluid-recycling loop, wherein treating the fluid includes— coagulatingthe submicron fragments to form coagulated submicron fragments in thefluid, and decreasing a concentration of the coagulated submicronfragments in the fluid.
 2. The method of claim 1 wherein coagulating thesubmicron fragments includes coagulating at least 90% by count of all ofthe submicron fragments of sieve diameter within a range from 0.005 to0.2 microns in a given volume of the fluid.
 3. The method of claim 1wherein: treating the fluid includes reducing a turbidity of the fluidfrom a first turbidity to a second turbidity; the first turbiditygreater than 1000 nephelometric turbidity units; and the secondturbidity is less than 5 nephelometric turbidity units.
 4. The method ofclaim 1, further comprising introducing makeup fluid into thefluid-recycling loop at a steady-state flowrate less than 2% of anoverall steady-state flowrate of the fluid within the fluid-recyclingloop.
 5. The method of claim 1 wherein decreasing the concentration ofthe coagulated submicron fragments includes concentrating the coagulatedsubmicron fragments into a volume of concentrate.
 6. The method of claim5 wherein a primary flowpath of the third portion of the fluid-recyclingloop passes through the volume of concentrate.
 7. A method, comprising:collecting a fluid contaminated with pulverized abrasive material in acatcher of a waterjet system; adding a chemical coagulant to the fluidso as to form coagulated pulverized abrasive material in the fluid, thechemical coagulant being soluble in the fluid to form a metallic ion anda counter ion, the metallic ion including iron, tin, copper, and/orsilver; and decreasing a concentration of the coagulated pulverizedabrasive material in the fluid.
 8. The method of claim 7 wherein themetallic ion includes copper.
 9. The method of claim 7 wherein thechemical coagulant is copper(II) sulfate.
 10. The method of claim 7wherein: the fluid contaminated with the pulverized abrasive materialhas a turbidity greater than 1000 nephelometric turbidity units; and thefluid with the concentration of the coagulated pulverized abrasivematerial decreased has a turbidity is less than 5 nephelometricturbidity units.
 11. The method of claim 7 wherein adding the chemicalcoagulant includes adding the chemical coagulant to cause a molarconcentration of the metallic ion in the fluid to be greater than 0.1millimolar.
 12. The method of claim 7, further comprising recycling thefluid for reuse in the waterjet system.
 13. The method of claim 12,further comprising pressurizing the recycled fluid to a pressure greaterthan 30,000 psi.
 14. The method of claim 13 wherein pressurizing therecycled fluid includes pressurizing the recycled fluid using adirect-drive plunger pump.
 15. The method of claim 7, further comprisingdecreasing a concentration of the metallic ion in the fluid.
 16. Themethod of claim 15 wherein decreasing the concentration of the metallicion includes contacting the fluid and a molecular sieve.
 17. A waterjetsystem, comprising: a pressurizing device configured to pressurize afluid to greater than 30,000 psi; a cutting head downstream from thepressurizing device, the cutting head being configured to direct a jetincluding the fluid toward a workpiece; a catcher positioned to collectthe jet; and a treatment assembly including a coagulation unit, wherein—the treatment assembly is configured to receive a contaminated fluidfrom the catcher and to remove submicron colloidal particles from thecontaminated fluid to form a treated fluid, and the treatment assembly,the pressurizing device, and the catcher are operably associated withone another within a fluid-recycling loop.
 18. The system of claim 17,further comprising a turbidity sensor operably connected to thefluid-recycling loop downstream from the coagulation unit and upstreamfrom the pressurizing device.
 19. The system of claim 17 wherein: thetreatment assembly includes a separation unit downstream from thecoagulation unit; the coagulation unit is configured to coagulate thesubmicron colloidal particles; and the separation unit is configured toseparate at least a portion of the coagulated submicron colloidalparticles from the contaminated fluid to form a treated fluid.
 20. Thesystem of claim 19 wherein the separation unit includes an in-streamfilter.